Electric generator



Oct. 30, 192s.

G. B. ROLFE ELECTRIC GENERATOR- Filed April 17, 1923 76 n laemoasmw lflTr'y.

GEoRGE BERKELEY n NoLEs, LIMITED, or

PATENT, OFFICE,I

oLEE, E LoNDolv, ENGLAND, ssIGNoR rro EVEESHED a VIG- LONDON, ENGLAND.

ELECTRIC GENERATOR.

Application led April l?, 1923, Serial No. 6

This invention relates to lmproveinents 1n magneto electric generators and has for 1ts Y 32,596, and in Great Britain nay 17, 1922.

portions only of rings may be equally well Iemployed to locate the pole pieces 1, 1 in object a construction whereby a machineof lproper relation to one another. As illuslight weight, high duty, and comparatively trated', the members 15, 15 of ring form are low cost of manufacture can be readily obarranged concentrically with the polar faces tained and a machine in which concentricity of the armature and the pole faces of the field magnet system is always obtained.

Referring to the drawings, which form 'part of this specificationy Figure 1 is a front elevat on of one form of magneto electricrnachine in which a pole piece unit constructed in accordane with this invention is employed, the' front bearing bracket'being removed to expose the armature.

Figure 2 is a transverse section of Fig. l taken on the line A-A showing how the unit locates the armature bearings.

Referring to Fig. 1, which illustrates a form r,of machine constructed in accordance with this invention, the field magnet system comprises pole pieces 1, l and permanent magnets 2, 2 arranged as al magnetic system.

The ends 8, 3, 3, 3 ofthe permanent magnets 2, 2 contact on either side .of the pole pieces 1, 1 with abutments'formed by projections 4, 4 on-the said pole pieces 1, 1 and are maintained in this position by a band 5. The -endsof the band 5 are turned into loops 6, 6 the ends 7 of the band 5 being rivetedto the main part of the band by rivets 8.

Within one of these loops 6 is disposed` a transverse member 9 having a hole. 10 through which the screw 11 passes, the other loop 6 having a transverse member 12 with a threaded hole 13 for receiving the threaded'end of the'. screw. 11. The loop 6 containing the transverse member 9 isv slightly cut away to enablefthe head 14 of the screw 1'1 to be turned bv a suitable instrument, the back sur- `face of .the head.l14 serving as an abutment to exert pressure on the band when turned; obviously, any analogous construction may be vemployed to retain the pole p-ieces 1, 1 'and' field maggets 2, 2 in thec'orrect relation;

The pole pieces 1, 1 are associated in proper relation the one to the other by riveting or otherwise securing them'to twomembers 15, 15 (see Fig. 2) of non-magnetic material, saidmembers in some cases and as illustrated being in the form of flat rings. Alternatively,

16, 1 6 o-the pole pieces 1, 1.

To support the armature 17 bearing brack- Aets 1.8 and 19 are provided said bearing brackets 18 and 19 being provided with recessed port-ions 20 and 21 respectively adapted on assembly with the pole pieces 1, 1 to engage withV the ring-like members 15, 15 aforesaid.

Obviously, when these members 15, 15 are of rin'g form as illustrated or are port-ions oi' rings andthe recesses 2O and 21 are concentric with the bearings 22, 22, the bearings 22,v

22 will be concentric with the polar faces 7 Referring to Fig. 2, it will be seen that suitable brushes 23, 24, 25 and 26, ar'ecarrie-d in housings 27 mounted on the bearing bracket 18. Instead of mounting all the brushes in housings 27 carried by the bearing bracket .18, some 'of the brushes'may be carried in housings supported by the bearing baclet 19 as is found most convenient. d The brushes are provided with suitable conductors for conveying the current collected thereby in. well-known `manner suitable insulating means being provided.

Jalthough for simplicity of descri manent magnets have been illustrated and referred tol obviously electromagnets or permanent with a winding-may be employed without departing from the scope of the invention.

I claim In a dynamo'electric machine', a pole piece unit having in combination two laminated pole pieces,v two locatinoF rings of non-magnetizablematerial rigidly and permanently connected to said pole pieces, said rings each having a circula@ external perimeter, and armature bearing brackets having recessed portions cooperating `with said circular perimeters for definitely locating the polar faces of the unit relative to the armature axis of the machine.

In testimony whereof I have signe name to this-s ecification.

GEOR E BERKELEY ROLFE.

d luy 

